Improvement in steam-engines



thdnl Seite SAMUEL D. TILLMAN,

OF NEW YORK, N.. Y.

Letters' Patent No. 113,818, dated April 18, 1871.

IMPROVMENT IN STEAM-ENGINES.

The Schedule referred t6 in these Letters Patent and making prt of the lame.

Be it known that I, SAMUEL D. TILLMAN, of the city, county, and State ofNeW York, have invented a new and useful Improvement ou the Steam-Engine; and I do hereby declare that. 'the following is a full,

clear, and exact' description of the"construction and operation of the same, reference being had to the annexed drawings making a part of this specitcation, in which-.-

- Figure l' is a perspective view;

vFigure 2 is alongitudinal elevation; and

Figure 3, a transverse section in all like letters referingto like parts.

A B CD is a compound cylinder made of metal and fastened irmly to the iron bed-plate T U V by means of the connections X Y. Each end of tue double cylinder is closed by means of the heads A D and B C.

Midway between them is another'. head or permanent partition, H H', which divides the cylinder into two equal parts, thus forming two separate and distinct cylinders having no direct connection with cach, by meansofthree heads. P1, fig. 2, is a reciprocating piston moving in the cyllnderA H D H.

R1 is the piston-rod attached to the/piston I" and passing through a lsteam-tight opening in the head A D. To the end of this rod It* is attached the cross-barGrl Il. At or near Il is an opening to receive the stationary4 rod L', which is parallel with the piston-rod Rl, arid permanently fixed by means ofthe pillars El F.

' The cross-bar Gr1 I moves by means of its connection with the piston-rod R, and, sliding on the stationary rod L, is kept constantly in the same right line.

At the extremity ofthe cross-bar Grl I1 is a pin passing through the connecting-rod M N1', nea-r the end M1, so arranged that the rod may move freely on the pin. Nearthe end N1 the connectingrod is attached to the vcrank-pin Kl in the wheel W2, around which pin it is free to move.

P2 is a reciprocating pistou moving in the cylinder B H H C, lig. 2."

' R2 is the piston-rod attached to P2, and passing through a steam-tight opening in the head B C. M Gr2 I2 is a cross-bar connected with the' piston-'rod R2. At or near the pointIzis an opening, throughwhich passes the stationary rod L2, fastened permanently by means of the pillars E F2.

The cross-bar Gr2 I, when moving with the pistonrod R2 is thus kept in the' same right line.

At the extremity of the cross-bar' GFL I2 is a pin passing through the connecting-rod M2 N2, near the end M2, so that the rod may move freely around the pin.

Near the end N2 the connecting-rod passes over the crank-pin K, which is free to turn within said rod. This connection is shown by the dotted lines in gs'. 1 and12.

The crank-pin K2 is fixed permanently to theshaft S, gs. 1. and 3,' and exactly at right angles with the crank-pin K1. To accomplish this the shaft S is permanently fixed in the wheels W1 and W2, andthe crankpin on the outside of each wheel in radial lines, ninety degrees apart, is at such distance from the center of the shaft that it will make just half a revolution around the shaft with each full stroke of the piston with which it is connected. lVhen one piston is at the end of its stroke and the crank-pin connected with it'is at the dead-point, the other .pistonis in the middle of its stroke and at its maximum velocity, exerting its power on' the crank-pin yconnected withit t the position of greatest leverage. The steam ,is appliedto each piston in the usual Way. The valves and passages for regulating the admission and exhaustion of the steam are not represented because they are precisely like those in ordinary nse,and ofthe uumber'rcquired for two separate engines.

yIn the most compact form of my engine, as represented in the drawings, where the shaft S passes through the H H head, the steam-chest and valves are on the top, and extending from A to B, tig. 1.

When the shaftS is placed over the cylinders, which requires the cross-bar G I1 and G? IZ to stand in a vertical position, the steam-chest maybe on either' side of the cylinders.

In constructing very small engines Von my plan the cylinders, center-head, and bed-plate may be cast in one piece; but in large engines the size of the shaft may requirethe center head to 'be constructed of two similar disks fastened firmly together. The power of the engine may be applied through either wheel W1 or Vif2 by bands or gearing. The advantages gained by my invention are- First, a great saving of power by preventing the loss ,of heat by radiation, for were the two cylinders entirely separated,.one side of two heads would radiate heat outward; but in my arrangement the center head is. constantly in contact with steam either' on one or both sides, and the heat radiated from the side not in contact with steam assists in keeping a cylinder hot.

Second, some of the' heat generated by friction of the shaft in the center-head is communicated to the steam in contact with this head, thus illustrating, on a small scale, an interesting anomaly inthe reconversion of heat expended into mechanical power.

Third, the saving in material, in substitutingv for two heads one, which also forms the journal for the revolving shaft.

Fourth, .the stability and durability of the engine secured by this close proximity of parts, especially when the main portion is castin one piece.- y

Fifth, the necessity for a iiy-wheel is obviated. This engine can be started from any position of rest, which is a very important advantage in small engines. There are many uses for the steam-engine whereicertain and instantaneous action is the greatest desideratma.

Although the arrangement described is especially adapted for 4the use of steam, yet common air or any other gaseous compound used as a motor may be substituted. Itis evident that the means employed' for guiding the piston-rods may be greatly varied by the designer. In some cases Ipropose to use rock-shafts as substitutes for the cross-heads. These rock-shafts would lieparallelwith the main' shaft, and' either above or below the piston-rods, and be provided each with two arms, the" inner ones to connect by links to the piston-rods and the outer ones to the connecting-rods.A

I am awa-re that engines have previously been made with two cylinders lying in the same line, and having axeoxnmon or two abutting cylinderheads. In one case the two pistons are connected together by side rods and operate one crank, which arrangement has no advantage over a common single engine. In another case the pistons connect directly in the usual way to separate shafts placed beyond the ends of the double-length cylinder, and the two shafts are connected by belts on their ily-wheels, or other extraneous Maele means. In my engine the power of both cylinders is transmitted outward bythe piston-'rods and back toward the center again bythe connecting-rods'. I use,

therefore, two back-acting engines, so called.

Captain Ericsson, in one of his patents, uses also two back-acting engines with the cylinders arranged similar to thoseabove described, but he connects through .bent levers to a single crank, on one side of the engine, the operating ends of the bent levers being arrangedabout ninety degrees apart with relation to the main shaft. In my engine the operating ends of the cross-heads and the main shaft are in the saine plane, and the connection is made to separate cranks4 placed at right angles on the main shaft.

-I claim as new and desire to secureby Letters Patent- Two back-acting engines, having cylinders in the same line and one common eylinder-head, when such engines are connected to-separate cranks set at right angles on the same shaft, and are arranged and combined substantially as described.

- SAMUEL D. TILLMAN. Witnesses: JOHN W. CHAMBERS, DAvn N. JAooBUs. 

